Agile Database development

(with Visual Studio)

Jose Luis Soria

Göteborg, April 2012

Jose Luis Soria

• ALM Team Lead at

Plain Concepts

• Professional Scrum

Trainer at scrum.org

jlsoria@plainconcepts.com

http://geeks.ms/blogs/jlsoria

@jlsoriat

Agenda

• Database development

• Agile development

• Agile database development

• Practices and tools

Database development

How databases work

• Databases are different from application code

– Application code is not changed while

running (even in dynamic languages, changes are not

persisted)

– Databases are changed while running

• Changes in data or database objects, made

while the database is online, have to be taken

into account while developing

Databases are changed while running

Take running database changes intoaccount while developing.

Have a proper policy for changes in place

Databases across environments

• We have to deal with several environments while developing

• Each environment has its own database

• These databases are used for different things

• These databases are in different states and versions, and contain different data

Databases are differentacross environments

Be prepared to change different thingsin different databases

Applying changes to databases

• Most times, any particular change can only be made one time. Once the change has been made, it is not possible to make it again

• Changes are difficult to be undone

Changes to databases are lastingand hard to be undone

Have a proper policy for changes in place.Have a proper policy for undoing

changes in place.

Agile development

Agile?

Twelve principles of AgileOur highest priority is to satisfy the customer through early and continuous delivery of valuable software.

Working software is the primary measure of progress.

Welcome changing requirements, even late in development. Agile processes harness change for the customer's competitive advantage.

Agile processes promote sustainable development. The sponsors, developers, and users should be able to maintain a constant pace indefinitely.

Deliver working software frequently, from a couple of weeks to a couple of months, with a preference to the shorter timescale.

Continuous attention to technical excellence and good design enhances agility.

Business people and developers must work together daily throughout the project.

Simplicity--the art of maximizing the amount of work not done--is essential.

Build projects around motivated individuals. Give them the environment and support they need, and trust them to get the job done.

The best architectures, requirements, and designs emerge from self-organizing teams.

The most efficient and effective method of conveying information to and within a development team is face-to-face conversation.

At regular intervals, the team reflects on how to become more effective, then tunes and adjusts its behavior accordingly.

Twelve principles of AgileOur highest priority is to satisfy the customer through early and continuous delivery of valuable software.

Working software is the primary measure of progress.

Welcome changing requirements, even late in development. Agile processes harness change for the customer's competitive advantage.

Agile processes promote sustainable development. The sponsors, developers, and users should be able to maintain a constant pace indefinitely.

Deliver working software frequently, from a couple of weeks to a couple of months, with a preference to the shorter timescale.

Continuous attention to technical excellence and good design enhances agility.

Business people and developers must work together daily throughout the project.

Simplicity--the art of maximizing the amount of work not done--is essential.

Build projects around motivated individuals. Give them the environment and support they need, and trust them to get the job done.

The best architectures, requirements, and designs emerge from self-organizing teams.

The most efficient and effective method of conveying information to and within a development team is face-to-face conversation.

At regular intervals, the team reflects on how to become more effective, then tunes and adjusts its behavior accordingly.

Agile database development

Early and continuous delivery of

valuable software.

Working software is the primary

measure of progress.

Welcome changing requirements. Sustainable development, constant

pace.

Deliver working software

frequently.

Continuous attention to technical

excellence and good design.

Business people and developers

must work together.

Simplicity.

Build projects around motivated

individuals. Give them the

environment and support they

need.

The best architectures,

requirements, and designs emerge.

What does it mean?

Early and continuous delivery ofvaluable software

Ability to deliver in a simple and quickway

Welcome changing requirements

Ability to introduce changesat any moment

Deliver working software frequently

Ability to deliver in a simple and quickway

Business people and developersmust work together

Development depends on business

Build projects around motivated individuals.Give them the environment they need

Proper environment and tools

Working softwareis the primary measure of progress

Development depends on business.Keep always

a functional version of the software

Sustainable development.Constant pace

Ability to introduce changesat any moment

Continuous attention to technicalexcellence and good design

Best practices: CI, refactoring, TDD…

Simplicity

Reuse.Work in small chunks

The best architectures, requirementsand designs emerge

Ability to introduce changesat any moment

Agile database development

Agile database development

• Be able to deliver database changes in a simple and quick way

• Be able to introduce database changes at any moment• Make database development dependent on business• Set up a proper environment and tools• Keep always a functional version of the database• Use best practices: CI, refactoring, TDD…• Reuse• Work in small chunks• Take running database changes into account while

developing• Have a proper policy for changes in place• Have a proper policy for undoing changes in place• Be prepared to change different things in different databases

How to do it?: practices & tools

Practices and tools

• Are going to help us to do database development properly

• Tools and demos for this session deal with relational databases (SQL Server). But principles are the same for other scenarios:– NoSQL (MongoDB, Azure Storage…)

– ORMs (Entity Framework, NHibernate…)

• Most things will also work with VS 11 and SQL Server Data Tools

Version control

• Treat database code like any other source code

– Enable several people to work on the same code base

– Make modifications available to the rest of the team in a controlled way

– Make it possible to set up Continuous Integration

– Use versioning features: compare, restore old version, combine…

• Use the same code, schema or approach to migrate any database in your environment

DemoVersion control for databases

Coding aids

• Visual Studio provides several aids for working with database code

– Intellisense

– Tracking and resolving dependencies

– Static analysis

– Refactoring

DemoCoding aids

Isolated development

environment

• Have each developer work in his own environment, which includes the database

– Self-contained

– Resembling production environment

– Automated (deployment, testing, etc.)

DemoIsolated development

environment

Unit tests

• Sometimes, database code can contain logic

• Database code can benefit from automated unit testing the same way as application code– Find problems early

– Facilitate change

– Simplify integration

– Self-document

– Drive the design

DemoDatabase unit testing

Continuous Integration

• Early warning of conflicting changes

• Immediate unit testing of all changes

• Constant availability of a "current" build for testing, demo, or release purposes

• Immediate feedback

• Modular, less complex code

• Quality code

Continuous Integration

principles

• Maintain a code repository

• Automate the build

• Make the build self-testing

• Everyone commits to the baseline every day

• Every commit (to baseline) should be built

• Keep the build fast

• Test in a clone of the production environment

• Make it easy to get the latest deliverables

• Everyone can see the results of the latest build

• Automate deployment

Continuous Integration

principles

• Maintain a code repository

• Automate the build

• Make the build self-testing

• Everyone commits to the baseline every day

• Every commit (to baseline) should be built

• Keep the build fast

• Test in a clone of the production environment

• Make it easy to get the latest deliverables

• Everyone can see the results of the latest build

• Automate deployment

DemoDatabase continuous

integration

Requirements drive changes

• Make changes in small chunks

• Changes are originated by requirements

• Make different changes for different requirements

Continuous deployment to any

environment

• Automating database migrations to any environment helps us:

– Easily roll forward or back

– Minimize disruption for changes

– Maximize reliability of deployment process

– Work incrementally (including DBAs)

Continuous deployment process

• Obtain the correct version of the

database

• Prepare the environment

• Initialize database and instance

• Initialize schema

• Initialize user credentials

• Populate database with reference data

• Have a rollback mechanism in place

DemoContinuous deployment

Database sync vs. delta scripts

• Syncing databases can lead to uncontrolled changes across environments

• It’s better to make changes the same way for all the environments

• We can use numerated delta scripts and tools like DBDeploy

Database sync vs. delta scripts

• Delta scripts– Great for greenfield development and Continuous

Integration

• Database sync– For legacy databases

– For non-agile, non-CI projects

– For changing data

– When you don’t have database under version control

• Other options– ORMs usually have their own mechanism to deal with

database changes. For example, migrations in Entity Framework

Dealing with data

• Reference data can be scripted

• Changes (delta scripts) should deal with existing data

• There are several ways to obtain data for testing– Using the application API

– Using backups

– Using data comparison tools

– Using data generation tools

Have we covered everything?

• Be able to deliver database changes in a simple and quick way

• Be able to introduce database changes at any moment• Make database development dependent on business• Set up a proper environment and tools• Keep always a functional version of the database• Use best practices: CI, refactoring, TDD…• Reuse• Work in small chunks• Take running database changes into account while

developing• Have a proper policy for changes in place• Have a proper policy for undoing changes in place• Be prepared to change different things in different databases

Any questions?

• Visual Studio Database tools http://bit.ly/dyN3wv

• VSDBCMD http://bit.ly/vB6G1

• Database changes done right http://bit.ly/wTOY01

• Continuous delivery http://continuousdelivery.com/

jlsoria@plainconcepts.com

@jlsoriat